Carburetor



Mmh .26, 1940. A, BREEZE 2,194,540

CARBURETOR Filed March 18, 1937 5 Sheets-Sheet l f6 O @M2220 Yi@ -f'fav@ '/9 /4 f2 Y' @9K 5.9 l B 0 5 66 Ml# f ./a f f6 I i @Y 7% 2 f5 w" 4Zy .ZZ g 4%@ l 4f ik I. O/Z W v 62 jf Z 154 2j) l W7C? eoffe/Ef/eeze.

H I /MMJW March 26, 1940.

G. A. BREEZE 2,194,540

CARBURETOR Filled March 18, 1937 3 Sheets-Sheet 2 CARBURETOR Filed March1s, 1937 s sheets-sheet s G. A. BREEZE 2,194,540 4 Patented Mar. 26,1940 yFi'A'FElT OFFICE oARBURE'roR George A. Breeze, Waterford Township,Oakland County, Mich.

t Application March 18',

2' Claims.

This invention relates to an improved and automatically controlled airvalve type of carburetor for-internal combustion engines.

It is an important object ofr this invention to provide an improved airvalve type of carburetor wherein the mixture ratio is varied betweenthat most suitable for maximum economy at different throttle settingsand that developing the most power, the change over in either directionbeing automatically accomplished by means responsive to whether the airvalve opens more or less than that opening normally corresponding to theexisting throttle opening. It will be evident that if the air valve doesnot open to a point corresponding to the throttle setting, then theengine is laboring or working under full power as its speed of rotationis not sufficient to demand enough air to openthe air valve to therequired extent. Under such circumstances, a richer or powerful mixtureis called for to enable the engine to develop its maximum power at thegiven throttle opening, even if such opening is v only partial.

exceeds that normal to a given throttle opening, theincreased speed willcause an increased opening of the air valve, under which circumstancesan ultra lean mixture isl automatically provided by the carburetor ofthis invention, thus economizing on fuel, reducing the overspeedingeffect v and serving to scavenge the cylinders and reduce the carbontherein, withouty damage to the engine because under these circumstancesthe load is lighter. t

It is a further object of this invention to provide an improved airvalve carburetor wherein the fuelmetering is under the coordinatedcontrolof both the air valve and the throttle, either of` which canautomatically dominate the metering control to provide either an economyor power. mixture ratio. y

It is also an object of this invention to provide ank air valve type ofcarburetor, wherein cams operated. separately by the air valve andthrottle coact with a fuel metering pin control, the arrangement beingsuch that the action of each cam on the metering control is subject toadjustment over the entire range, and the heels and toes of each cam areseparately adjustable to vary the mixture control at the extremes With-Contrawise, when the engine speed 1937, Serial No.y 131,575 (Cl. 261-49)It is still another object of this invention to provider an improved.and simplied choke control for enrichening the mixture for startingpurposes, the choke control being arranged to cooperate with both theair valve` and the fuel metering control to progressively increasethespring load on the air valve, and to increase the fuel supply, as wellas beingso coordinated with the air valve `that a rapid opening thereofwill release the choke control.

Other and further objects of thisinvention will become apparent from thefollowing disclosures., taken in. connection With the accompanyingdrawings, in which: Figure 1 is a top plan View of a carburetorembodying the features of this invention;

' Figure 2 is an elevation of the throttle lever or front side ofrthevcarburetor;

Figure 3 is an elevation of the throttle cam or rear side of thecarburetor;

` Figure 4 is a. front central vertical section of the carburetor, withparts shown` in elevation, corresponding to the section line IV--IV- ofFigure l;

Figure 5 is a section 4, showing the fuel. bowl and float mechanism;

Figure 6 is a'section on the line VI-'VI of Figure 2, showing theaccelerator pump and dash pot construction; l

Figure '7 is a fragmentary detail section taken along. the line.VII--VII of Figure 1,. showing the choke or mixture enrichening control;and

Figure 8fk is a distorted diagrammatic outline layout of the cooperatingair valve and throttle 'linkages controlling the fuel metering pin.

As shown on the drawings:

The improved air valve type. of carburetor of this invention has beenshown as of the downdraft type in the accompanying drawings, al- 'thoughit will be evidentthat the invention is not limited to the illustratedVform. Thev carbn. the une v--v of Figure buretor, as illustrated,comprises three. members f through which. `the mixture passagecontinues. The uppermost member or casing H has anl external seat I2 toreceive an air cleaner and is internally proled at i3 to cooperate withan air valve I4. It also provides bearings for a cross-shaft I5 carryingapower cam I5 at one end.

The center member I'I provides a continuation .IB of the mixture passageand has a projecting portion I9 which serves as a fuel chamber cover,the cover also providing a bearing for a metering control shaft 25. Theair valve I4 is slidably mounted on a vertical guide 2l mounted in abridge 22 across the mixture passage I8.

The lower member 23 contains a Venturi passage 24 forming a continuationof the mixture passage I8, a throttle shaft 25 being located in thelower portion of the Venturi passage adjacent a carburetormountingflange 26. rlhe lower member 22 also embodies a fuel chamber 2and an accelerating pump and dash pot chamber 28. The fuel chamber 2lcontains a float 29 which actuates a fuel admission valve 35 controllingthe entry of fuel from a source of supply 3i.

VThe'fuel chamber 2l' extends partly around the barrel of the lowermember 23 in order to provide more reserve fuel and to place a fueloutlet passage 32 approximately centrally of the fuel volume, in orderto maintain the normal fuel level at the passage 32, in spite of unusualinclinations of the carburetor as a whole. The passage 32 comprises atube depending from the center member and communicating withl a passage33 in the -bridge 22, from which a fuel spray nozzle 34 extendsdownwardly (in the case of a down draft carburetor) into the restrictedzone of the Venturi passage 24. The fuel chamber also communicatesthrough a passage 35 with the bottom of the dash pot and acceleratorpump chamber 28, aball check valve 35 being provided at the bottom ofthe chamber 28 to prevent return flow of fuel.

The air valve I4 is slidably mounted on a guide 2l forming an extensionof the fuel nozzle, the guide being passaged at'S'l to receive an airvalve vspring 3i), the calibration of this spring in relation to theprofile of thev passage I3 about. the air-valve being'such that as theair valve opens, the mixture tends to be progressively leaned byt thecontrol mechanism to be hereinafter mentioned. In other words, thespring is purposely made lighter than would be required to maintain auniform fuel and air ratio as the valve I4 opens. It will be evident inthis connection that the chosen spring rate orstrength determines thedepression range within the carburetor in response to engine suction,and the length of the spring controls the initial depression required toopen the air valve. Control of the fuel supply to the nozzle 34centersabout a metering pin 3S cooperating with a tapered section in thehorizontal fuel passage 33.' The pin 39 is of cylindrical section withan external head 4I backed by a light spring 42 which retracts the pin,the controlled proximity of the pin to the taperedsection 45 meteringthe `flowof fuel to the nozzle 34. The pin 39 is operated by a bellended lever 43 secured to the metering control shaft 2B which in turn isactuated by either the power cam I5 on the cross-shaft l5 or a throttlecam 44 on the throttle shaft 25.

' The cross-shaft l5 carrying the power cam I5 is actuated by a ballended lever 45 slidable in a horizontal guide passage 46 in the airvalve I4, so that an opening movement of the air valve causescounter-clockwise rotation `of the cross- 2,194,54o f f f shaft I5 inFigures 4 and 8. The powercam I 6 cooperates with a short armed lever 41on vone end of the metering control shaft 2li, adjustment being providedby means of a set screw 48. Similarly, the throttle cam 44 cooperates bymeans of a rod 49 with a long armed lever 50 on the control shaft 2l),another set screw 48 providing for adjustment between the lever 59) andthe rod 49. f

The cams l5 and 44 are somewhat similar in construction in that anadjustable spring face 5I is utilized, the center portion of which is inconv The power cam I6 limits the rise of the short lever 4l and therebylimits the opening movement of the metering pin. The opening ofthe fmetering pin in relation to theope'ning of the air valve is4 thuscontrolled by the contour of the power cam throughout the power range.It is thus possible to provide varying fuel ratios for varyingconditions over the entire speed range of an engine, as by'varying thelower end 54. of the cam for adequate pick up, and thevupper end forhigh speed operation, without affecting the central portion of therange, which latter is adjusted `by means of the screw 48 in the shortlever 4l which modifies the whole range.

The throttle cam 44 provides a driving range mixture control'whichprovides a normally leaner mixture ratio than thepower cam I6, so thatthe cam 44, acting through the push rod 49 on the long lever 55,normally holds the'short lever 4'! out of contact or away froml thepower cam I5. The throttle cam 44 has its spring face 5I calibrated for'best economy on a given engine and car load for constant speeds on alevel road. A screw 55 on the end 5l' of the cam nearest the push rod49, when the throttle is closed for idling, serves to provide the idlingadjustment, which is made directlyoln the fuel through the metering pin39, and blends smoothly into the higher speeds as-thethrottle is openedWithout a transition point or spot, as when a conventional idling bypassis used. The adjusting screw 48 in the long lever 55 varies the mixtureover the whole partial throttle opening range, while the idlingadjustment screw 56 affects only the lowest or idlingspeeds The throttleposition determines the metering pin location under normal conditions atany partial throttle opening, the air valve being free to open or closeaccording to the air passing through the engine will run slower at agiven throttle l openingr so that the air valve will not open as far,and the mixture will be correspondingly richer. If, however, the engineload is lighter and the engine-runs faster, as on a down-grade, or whenthe throttle ris closed for deceleration,

the air valve will open farther than the throttle.

position would demand normally andthe mixture will be leaner. This-leanmixture, characteristic when-the engine temporarily speeds up, tends toburn out carbon, and does-no harm to the engine because it doesnotoccurunder load and is of short duration.

When the throttle is opened for acceleration, the power cam lf3 comesinto play as the throttle cam 44 rotates far enough to drop the pushrody 49k out of contact with the longlever 50, allowing the power cam tocontrol the metering pinS through contact with the short lever v1W, sothat coincident with the throttle opening the `mixture is enriched tothat calibration chosenfor bestpower at the given speed as determined bythe air valve opening andthe contour of the power cam I6.

if the throttle is openedy slowly venough sov that the air valve i4 doesnot jump, no extra accelera-Y` tion fuel is required, as a gradualopening of the air vaive supplies more fuel in step therewith, the ratiobeing determined by the power cam profile and the proleof the air valveand its profiled passage, the two profiles being preferably so laid outthat the air valve travelwill be proportional to the increasing volumeof Aair admitted past the valve in order to simplify the requirements ofthe profile of the cam I6.

The crossshaft i5 carries a lever 58 which operates a rod Eii carrying apiston Gil loosely tting'in the accelerating pump anddashhpot chamber28, the arrangement bein-g such that a slow opening movement roi? theair valve will move the piston downwardly in the chamber at a speed slowenough to allow the fuel therein to bypass around vthe piston. On theother hand, a rapid downward movement of the l piston will applypressure on the fuel there-- below, since the ball check dii will closethe fuel passage Accelerating fuel is taken from the chamber Z throughaport 5| in the wall considerably above the bottom of the piston stroke,thisy port leading to a' valve seat 62 controlled by a weighted valvewhich lifts in response to fuel pressure toailow fuel to be dischargedthrough `a passage leading to an accelerating jet 65. rihe valve isported at ii to commu-k nicate with the air above the fuel in the fuelchamber to kill any suction tending-to lift the valve t3. The travel ofthe valve t3 is limited hy the cover it after it has been yforced openfar enough to shut off the air ports'li to prevent fuel from beingdischarged therethrough. Preferably, the valve G3 is a loose fit in itsguide so that some of the fuel escapes around the sides f the valve, assuch an. arrangement permits the use of a larger drill Vin theaccelerator jet S which is proportioned to the acceleration requirementsoi the engine on which the carburetor is to be used. ,v

If the throttle is opened suddenly, the air valve moves rapidly and theclearance around the piston til is insuicient'to allow fuel toy escape,causing delivery of accelerating fuel until the piston tl covers theport ill. 'Thereaften the piston serves only as a steadying dash pot bymeans of -a choke control which acts `to progressively add increasingspring 'tension opposing the opening of 4the air'valve'and to' retractthe meteringpin 39 to also increase the fuelv ilow. This is accomplishedby means of afchoke lever 66 adjustably. mounted on a' U-shaped bracketmember ci which is pivoted on a stub shaft 68 between the cross shaft I5and the metering control shaft 2@ as this mechanism acts onboth.shafts... v

An initial slight movement oi the choke lever 5 brings the Ushapedbracket member t? into contact with one end t9 of'` ay torsion springlil on the cross-shaft it, the other end 7l of the `spring engaging theaccelerator lever 5i! so that continued clockwise movement oi' thebracket member t? in Figure 7 imposes additional spring load on the airvalve ill. Simultaneously, a lug l2 on the bracket member 61 moves tocontact a stop 3 carried by the metering shaft 20 in a direction Itorotate the shaft and increase the opening the metering pin 3S. Thebracket and spring `strength is such that the spring. will hold againstcranking speed engine suction, but will allow the air valve to open whenthe engine starts, and if the motor is raced withthe choke on, the addedforce acting on the air valve tends to kick off .the choke, thusreleasing the same and returning the carburetor to normal operatingconditions.

Since the .cams 'It and it act on the long and short levers 5t and 4l torestrain opening movement of the metering pints, it is necessary, to

, provide the .foregoing choke operation, that the shaft it be movablerelative to the levers. To this end, the two levers are mounted on asleeve l'i rotatable on the shaft 2G, and a torsion spring` 4cams I6 andt,

For further eiiiciency in starting, a small aperture 'dll in the centerof the air valve lll communicates through the tubular extension of thefuel nozzle ywith the nozzle 3ft proper. This air passage is small, and`at starting speeds the suction in the carburetor produces a high airvelocity which eiects a good atomization of the lfuel entering` thenozzle, thus helping startin and minimizing crankcase dilution.

The profile vof the air passage i3 is 'very important, as air velocitiescontrolled by the relative contours of the' air valve and passage wallsare worked out to permit the use of lighter air valve springs and toobtain air valve travel and .power cam movement proportional to thevolume of air flow. This air valve spring is worked out so light that ifthe air valve is opened by engine suction `without a correspondingincrease in the metering pin opening, a leaner mixture results. Thisgives the carburetor its unique automatic mixture changingcharacteristics with partial throttle openings. At higher engine speeds,the lower side of the air valve rides on a very high velocity air streamand is thus prevented from snapping wide open because of th vusevof aslight spring. v

It will thus be seen that I have invented an improved air valve type ofcarburetor wherein the faults common to previous air valve carburetorshave been eliminated by the use of an Ulv air valve arranged to move inproportion to the volume of air flowing therepast and opposed by arelatively light spring which provides a char acteristic tending to leanthe mixture as the valve opens, in combination with a power cam operatedby air valve movement to controllably increase the fuel flow, wherebywhen the engine operates at a higher speed than normal for a giventhrottle opening, as when the engine is lightly loaded, the mixturewillbe leaned out, while when the engine is operating slower thannormal, as when pulling hard for a given throttle opening, such asoccurs during warm-up, acceleration and hill-climbing, the mixture willbe automatically enrichened to a varying power mixture determined by anadjustable cam operated by the air valve. The carburetor of thisinvention thus provides an automatically adjustable mixture controlproviding maximum economy for normal operation and the maximum powerobtainable from an enrichened mixture when operating conditions sorequire.

I am aware that many changes may be made and numerous details ofconstruction may be varied through a wide range without departing fromthe principles of this invention, and I, therefore, do not purposelimiting the patent granted hereon otherwise than is necessitated by theprior art.

I claim:

l. In a carburetor of the air valve type, an air valve, spring meansurging said air valve to closed position, a fuel supply reservoir, anozzle in communication with said reservoir, fuel meteringrneansincluding a fuel valve, spring means urging said fuel valve to openposition, a first cam connected with said air valve and oscillable bymovement of said air valve, a first cam fol` lower operably connectedwith said fuel valve, a throttle, means including a second cam and asecond cam follower operably connected with saidthrottle and linked withsaid fuel valve,

both of said cam followers being arranged to llimit opening movement ofsaid fuel valve, said second cam and said second follower being'soconstructed and arranged as'to permit opening of vsaid fuel valve uponpart opening or" said throttle until prevented by engagement of saidrst-'mentioned cam with said first follower, further opening of saidthrottle beyond a predeterminedpart opening being effective to disengagesaid second cam and said second follower from control of said fuel valveand to put said air valve in complete control of said fuel valve.

2. In a carburetor of the air valve type, spring means urging said airvalve to closed position,

a fuel supply reservoir, a nozzle in communication with said reservoir,fuelv metering means including a fuel valve, spring means urging saidvalve to open position, a follower operably connected with said fuelvalve, a throttle, a first ing movement of said fuel valvel while saidthrot` tle is being turned through a range of from closed position to aposition of predetermined part opening, said first means comprising amovable cam member connected movable with said air valve and engageableby said follower, and said second means comprising a movable memberconnected movable with said throttle and engageable with said follower,said second means being arranged to move said foilower out of engagementwith said cam member and to adjustably limit opening of said fuel valvewhile said throttle is being turned from a predetermined position ofpartial opening to closed position.`

GEORGE A. BREEZE.

